incidence of ocular hypertension following silicone oil

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Citation: Nariani A, Khanna N, Chawla A, Momi R, Gabrielian A, et al.(2015) Incidence

of Ocular Hypertension Following Silicone Oil Use after Vitrectomy Surgery. Int JOphthalmol Clin Res 2:023

Received: February 09, 2015:Accepted: May 11, 2015:Published: May 14, 2015

Copyright: 2015 Nariani A. This is an open-access article distributed under the terms

of the Creative Commons Attribution License, which permits unrestricted use, distribution,

and reproduction in any medium, provided the original author and source are credited.

Nariani et al. Int J Ophthalmol Clin Res 2015, 2:2

ISSN: 2378-346X

Incidence of Ocular Hypertension Following Silicone Oil Use afterVitrectomy Surgery

Ashiyana Nariani, Nitasha Khanna, Arthi Chawla, Rominder Momi, Anna Gabrielian and

Seenu M. Hariprasad*

Department of Ophthalmology and Visual Science, University of Chicago, USA

*Corresponding author:Seenu M. Hariprasad, M.D., Professor and Director of Clinical Research, Department of

Ophthalmology and Visual Science, University of Chicago, 5841 South Maryland, MC 2114 Chicago, IL 60637, USA,

E-mail: [email protected]

SO implantation has been difficult to ascertain rom the literaturebecause o this variable presentation [4].

Te purpose o our study was to assess the incidence o SOIOHat our institution, afer 1000cs SO was implanted in patients requiringsilicone oil tamponade (SO) afer pars plana vitrectomy (PPV).Additionally, we analyzed each patients age, amily history oglaucoma, length o SO, and presence o retained SO and changes inIOP, in order to better understand the various actors that contributeto SOIOH.

Patients/Materials and Methods

We did a retrospective chart review o patients with SO orvarious etiologies between 2005 and 2008, including tractional retinaldetachment, rhegmatogenous retinal detachment, prolierative

vitreoretinopathy, and macular hole. A standard three port pars planavitrectomy with 1000cs SO injection was perormed. All patientsunderwent three consecutive air-fluid exchanges upon SO removal.No patient had SO overfill. As it is customary in our practice, all hadsmall fluid menisci to ensure absence o overfill.

Te main outcome was the development o SOIOH in theoperated eye. SOIOH was defined as IOP greater than 20mmHg aferpost-operative week #3 requiring therapy. Patients who developedSOIOH were compared to those who did not (SOIOH ree group), interms o age, amily history, length o SO, presence o retained SO,and IOP outcomes. IOP values in the SOIOH, SOIOH ree and thecombined groups were compared with the paired t-test.

Patients with SO overfill or IOP spikes on post-operative days1-21 were excluded. Additionally, patients with glaucoma, ocularhypertension, glaucoma suspects and those on IOP lowering agentswere also excluded.

AbstractBackground and objective: Silicone oil (SO) is important in

vitreoretinal surgery. The incidence of glaucoma after silicone oil

tamponade (SOT) was investigated.

Study design/patients and methods:A retrospective chart review

of patients with SOT at the University of Chicago from 2005 to 2008

was conducted to determine the incidence of Silicone Oil Induced

Ocular Hypertension (SOIOH). IOP in the SOIOH and SOIOH free

groups was compared with the paired t-test.

Results:45 eyes were evaluated.15 developed SOIOH. Average

length of SOT was 10 months in the SOIOH group versus 7.3 months

in the SOIOH free group. IOP in the SOIOH group increased by 9.9

1.8mmHg (p=0.0001; CI: 6.13-13.73) and by 0.97 1.0mmHg

(p=0.36; CI: -1.15-3.08) in the SOIOH free group.

Conclusions:One-third of patients with SOT developed SOIOH.

Given the association between length of SOT and incidence of

SOIOH, SO removal should not be delayed.

Introduction

Silicone oil (SO), also known as polydimethylsiloxane, is asynthetic polymer made o consecutive Si-O units [1]. It was firstintroduced by Cibis in 1962 or use in retinal detachment surgery [2].oday, SO is an important adjunct or internal tamponade in a wide

variety o vitreoretinal surgeries, especially in eyes with prolierativevitreoretinopathy and diabetic tractional retinal detachments.Silicone oil has unique chemical characteristics that make it a useul

tool in intraocular tamponade. Tese include an effective buoyantorce and high surace tension [3]. Tere are currently two types oSO available to use in vitreoretinal surgery. Te two different SOs aredifferentiated based on viscosity. Te 1000cs SO is less viscous and hasa lower molecular weight, and the 5000cs SO is more viscous and hasa higher molecular weight [4].

Unortunately, SO has been associated with complications, suchas cataract, keratopathy, and glaucoma [5-9]. Secondary glaucomahas been reported to occur at any time in the post-operative period.Tis secondary glaucoma can maniest with a wide range o IOPs and

vision loss [4,5,10]. Te true incidence o secondary glaucoma afer

Table 1: Characteristics of SOIG and SOIG free patients

SOIGGroup SOIG Free Group

Number of eyes N=15 (33%) N=30 (67%)

Age (years) 50.5 (range 2-73) 40.2 (range 7-76)

Family history of glaucoma 6/15 (30%) 6/30 (15%)

SOIG: Silicone Oil Induced Glaucoma, SOT: Silicone Oil Tamponade, SO:

Silicone Oil, IOP: Intraocular Pressure


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pathogenesis responsible or early onset SOIOH. Tese include: 1)pupillary block 2) inflammation 3) pre-existing glaucoma, and 4)

migration o silicone oil into the anterior chamber with subsequentmechanical obstruction to filtration [4]. Tis contrasts with thepossible mechanisms or intermediate and late-onset SOIOH, whichare: 1) infiltration o trabecular meshwork by SO bubbles 2) chronicinflammation 3) synechial angle closure 4) rubeosis iridis 5) migrationo SO (emulsified and non) into anterior chamber [4]. It is difficult toascertain the relative contribution o these individual actors to thedevelopment o SOIOH. Tis could be because the exact timing oearly, intermediate and late onset o SOIOH are poorly defined in theliterature.

In our study, SO with 1000cs SO afer PPV seemed to beassociated with the development o SOIOH in 33.3% o patients.Literature review shows that the true incidence o glaucoma afer SOis difficult to establish, with averages rom previous studies (1979 to2007) ranging rom 0-56% [4].

We excluded patients with acutely elevated IOP in order toinvestigate a more homogenous group o patients. Tese includedpatients who had non-sustained IOP spikes in postoperative days 1-21and patients with SO overfill. SO overfill can lead to acute glaucomawith shallowing o the anterior chamber and oil displacement intoanterior chamber [3]. As a result, all patients had a small meniscuso silicone oil to ensure the absence o overfill. Additionally, as iscustomary in our practice, all underwent three consecutive air-fluidexchanges upon SO removal to ensure that all oil had been removed.

Age and amily history o glaucoma had a positive correlationwith the development o SOIOH. Tis is consistent with the tendency

o glaucoma to be an age-related disease. One third o patients withSOIOH had a positive history o glaucoma, which supports ourknowledge that genetic predisposition is an important part o themulti-actorial nature o glaucoma, and has important implicationsor patients undergoing SO.

Te length o SO was associated with increased incidence oSOIOH. Tis suggests that SO should be removed as soon as thereis no urther need or it. Unortunately, the majority o patients withSOIOH had persistence o the disease, even afer SO removal. Tiscould imply that the pathogenesis o SOIOH includes irreversibledamage to the angle structures. Additionally, small silicone bubblescould have persisted in the trabecular meshwork, even afer oilremoval. Patients with SOIOH were 1.7 times more likely to haveretained SO in the anterior segment. Retained SO in the anteriorsegment could increase the risk o developing SOIOH. Patients in theSOIOH group had a 10 old higher increase in average post-operativeIOP.

In our study the incidence o retained silicone oil was 20% and33%, in the disease ree and SOIOH groups respectively. Even thoughdata on incidence o retained silicone oil is limited in literature, arecent study ound that 17% o patients retain silicone oil in theanterior chamber afer repair o complex retinal detachments withsilicone oil tamponade [11]. Patients with SOIOH were 1.7 timesmore likely to have retained SO in the anterior segment. Retained SOin the anterior segment could increase the risk o developing SOIOH.Notably, there is potentially a correlation between lens status andretained SO. 5 o 6 (83.3%) in the SOIOH ree group with retained

SO where phakic. 2 o 5 (40%) in the SOIOH group with retainedSO where phakic. Another 2 o 5 (40%) in the SOIOH group withretained SO were aphakic. All patients undergoing SO had increasedIOP post-operative, with SOIOH group having a nearly 10 old higherincrease in IOP.

Results

Forty-five patients that met the criteria were evaluated. Tedemographics o the SOIOH ree group and the SOIOH group aregiven in able 1. Te average age o all the patients was 43.5 years(range 2-76). Te mean ollow-up was 21 months (range 6-60). Teaverage length o SO was 8.2 months (range 4-38). Average pre- andpost-operative IOP or the combined group was 13.6 4.6mmHgand 17.5 7.9mmHg respectively. IOP increased by 3.6mmHg(1.1mmHg; p=0.0009; 95% CI: 1.74-6.17) overall post-operativelyor the combined group.

Fifeen o orty-five patients (33.3%) developed SOIOH. SOIOHgroup had an average IOP o 12.7 3.8mmHg pre-operatively and22.6 8.4mmHg post-operatively. Average IOP in the SOIOH groupincreased by 9.9mmHg (1.8mmHg; p=0.0001; 95% CI: 6.13 to 13.73)(able 2).

Te SOIOH ree group had an average pre-operative IOP o 14.0 4.84mmHg and a post-operative IOP o 15.0 6.2mmHg. Overallthere was an increase in the IOP by 0.97mmHg (1.0mmHg; p=0.36;95% CI: -1.15 to 3.08) post operatively.

Six o thirty (20%) patients in the SOIOH ree group and 5 o 15(33%) in the SOIOH group had retained silicone oil in anterior chamberafer SO removal (Figure 1). O the 6 patients with retained SO in theSOIOH ree group 5 were phakic and one had a posterior chamber

intraocular lens (PCIOL). In the SOIOH group 2 out o 5 patient withretained SO were phakic, 1 had a PCIOL and 2 were aphakic. All 11patients with retained silicone oil in anterior chamber had oil visible inthe anterior chamber. wo o the eleven patients (1 rom each group)had silicone bubbles in the anterior chamber and angle.

Te average time to develop SOIOH was 9.7 months (range 1-38).Tirteen o fifeen eyes (87%) had persistent SOIOH even afer SOremoval. SOIOH resolved afer SO removal in 2 o the 15 patients withSOIOH. In one patient SOIOH resolved afer having an additionaltrip to the operating room to remove persistent SO droplets rom theanterior chamber by washout. Te rest o the SOIOH patients weremanaged medically.

Discussion

Te development o SOIOH can be categorized according tothe postoperative time o onset. SOIOH that develops early in thepostoperative period has a different pathogenesis than intermediate-and late onset SOIOH. Tere are many proposed mechanisms o

Table 2:Results

Average preoperative

IOP (mmHg)

Average postoperative IOP

(mmHg)

Length of SOT

(months)

Average increase in IOP

(mmHg)

Retained SO in anterior

chamber after SO removal

SOIG group 12.7 3.8 22.6 8.4 10 (3-38) 9.9 1.8 (p=0.0001) 5/15 (33%)

SOIG free group 14.0 4.84 15.0 6.2 7.3 (3-17) 0.97 1.0 (p=0.36) 6/30 (20%)

SOIG: Silicone Oil Induced Glaucoma, SOT: Silicone Oil Tamponade, SO: Silicone Oil, IOP: Intraocular Pressure

Figure 1:Visible silicone oil in the anterior chamber of a patient lying supine.


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References

1. Kreiner CF (1987) Chemical and physical aspects of clinically applied

silicones. Dev Ophthalmol 14: 11-19.

2. CIBIS PA, BECKER B, OKUN E, CANAAN S (1962) The use of liquid silicone

in retinal detachment surgery. Arch Ophthalmol 68: 590-599.

3. Gallemore RP, McCuen BW (2006) Silicone oil in vitreoretinal surgery. In:

Ryan SJ ed. Retina, (4thedn). St Louis: Mosby: 2211-2234.

4. Ichhpujani P, Jindal A, Jay Katz L (2009) Silicone oil induced glaucoma: a

review. Graefes Arch Clin Exp Ophthalmol 247: 1585-1593.

5. Barr CC, Lai MY, Lean JS, Linton KL, Trese M, et al. (1993) Postoperative

intraocular pressure abnormalities in the Silicone Study. Silicone Study

Report 4. Ophthalmology 100: 1629-1635.

6. Chan C, Okun E (1986) The question of ocular tolerance to intravitreal liquid

silicone. A long-term analysis. Ophthalmology 93: 651-660.

7. Federman JL, Schubert HD (1988) Complications associated with the use

of silicone oil in 150 eyes after retina-vitreous surgery. Ophthalmology 95:

870-876.

8. Leaver PK, Grey RH, Garner A (1979) Silicone oil injection in the treatment

of massive preretinal retraction. II. Late complications in 93 eyes. Br J

Ophthalmol 63: 361-367.

9. Nguyen QH, Lloyd MA, Heuer DK, Baerveldt G, Minckler DS, et al. (1992)

Incidence and management of glaucoma after intravitreal silicone oil injection

for complicated retinal detachments. Ophthalmology 99: 1520-1526.

10. Zborowski-Gutman L, Treister G, Naveh N, Chen V, Blumenthal M (1987)Acute glaucoma following vitrectomy and silicone oil injection. Br J Ophthalmol

71: 903-906.

11. Ozdek S, Yuksel N, Gurelik G, Hasanreisoglu B (2011) High-density silicone

oil as an intraocular tamponade in complex retinal detachments. Can J

Ophthalmol 46: 51-55.

12. Petersen J, Ritzau-Tondrow U (1988) Chronic glaucoma following silicone oil

implantation: a comparison of 2 oils of differing viscosity. Fortschr Ophthalmol

85: 632-634.

13. Stinson WG, Small KW (1994) Glaucoma after surgery on the retina and

vitreous. Semin Ophthalmol 9: 258-265.

Anterior chamber washout was done in one patient with retainedSO in the anterior chamber afer SO removal due to persistentlyelevated IOP despite maximum medical management. Tis resulted insuccessul resolution o SOIOH. Te remaining patients with SOIOHwere managed medically. No patient required surgical management oSOIOH. Given the success o anterior chamber washout in resolvingSOIOH, it should be attempted in all patients with persistentlyelevated IOP and visible SO in the anterior segment.

Tere is conflicting data regarding the development o SOIOH

afer the use o the 1000cs or 5000cs SO. For example, one studysuggested the 1000cs is more likely to cause an elevated IOP [12],but another study did not find such a difference [13]. Tereore, itwould be plausible to investigate 1000cs compared to 5000cs SO ina prospective, randomized controlled study, in order to determinei there is a significant difference between the two oils in causingSOIOH. Tis could potentially lead us to modiy our use o silicone oilby selecting the saer oil or SO in the near uture. Additionally, theissue o ocular hypertension with the current management o SO,may be overcome through the development o a non-SO vitreoussubstitute in the uture.

Our study was limited by its retrospective nature and a relativelysmall number o patients. We defined SOIOH to be a persistent

elevation o IOP afer post-operative week #3. Were this a prospectivestudy, we would have included visual field and pachymetry testingto define the SOIOH group with more accuracy. Despite theselimitations, however, our ollow-up suggested that over one thirdo patients with SO develop SOIOH, with length o SO beingassociated with an increased incidence o SOIOH. Since the majorityo patients continue to have persistent SOIOH even afer SO removal,SO should be minimized as much as possible, without compromisingthe success o the surgery.
http://www.ncbi.nlm.nih.gov/pubmed/3653471http://www.ncbi.nlm.nih.gov/pubmed/3653471http://www.ncbi.nlm.nih.gov/pubmed/14021325http://www.ncbi.nlm.nih.gov/pubmed/14021325http://www.ncbi.nlm.nih.gov/pubmed/19685070http://www.ncbi.nlm.nih.gov/pubmed/19685070http://www.ncbi.nlm.nih.gov/pubmed/8233387http://www.ncbi.nlm.nih.gov/pubmed/8233387http://www.ncbi.nlm.nih.gov/pubmed/8233387http://www.ncbi.nlm.nih.gov/pubmed/3725324http://www.ncbi.nlm.nih.gov/pubmed/3725324http://www.ncbi.nlm.nih.gov/pubmed/3174036http://www.ncbi.nlm.nih.gov/pubmed/3174036http://www.ncbi.nlm.nih.gov/pubmed/3174036http://www.ncbi.nlm.nih.gov/pubmed/465413http://www.ncbi.nlm.nih.gov/pubmed/465413http://www.ncbi.nlm.nih.gov/pubmed/465413http://www.ncbi.nlm.nih.gov/pubmed/1454317http://www.ncbi.nlm.nih.gov/pubmed/1454317http://www.ncbi.nlm.nih.gov/pubmed/1454317http://www.ncbi.nlm.nih.gov/pubmed/3426996http://www.ncbi.nlm.nih.gov/pubmed/3426996http://www.ncbi.nlm.nih.gov/pubmed/3426996http://www.ncbi.nlm.nih.gov/pubmed/21283158http://www.ncbi.nlm.nih.gov/pubmed/21283158http://www.ncbi.nlm.nih.gov/pubmed/21283158http://www.ncbi.nlm.nih.gov/pubmed/3220375http://www.ncbi.nlm.nih.gov/pubmed/3220375http://www.ncbi.nlm.nih.gov/pubmed/3220375http://www.ncbi.nlm.nih.gov/pubmed/10155647http://www.ncbi.nlm.nih.gov/pubmed/10155647http://www.ncbi.nlm.nih.gov/pubmed/10155647http://www.ncbi.nlm.nih.gov/pubmed/10155647http://www.ncbi.nlm.nih.gov/pubmed/3220375http://www.ncbi.nlm.nih.gov/pubmed/3220375http://www.ncbi.nlm.nih.gov/pubmed/3220375http://www.ncbi.nlm.nih.gov/pubmed/21283158http://www.ncbi.nlm.nih.gov/pubmed/21283158http://www.ncbi.nlm.nih.gov/pubmed/21283158http://www.ncbi.nlm.nih.gov/pubmed/3426996http://www.ncbi.nlm.nih.gov/pubmed/3426996http://www.ncbi.nlm.nih.gov/pubmed/3426996http://www.ncbi.nlm.nih.gov/pubmed/1454317http://www.ncbi.nlm.nih.gov/pubmed/1454317http://www.ncbi.nlm.nih.gov/pubmed/1454317http://www.ncbi.nlm.nih.gov/pubmed/465413http://www.ncbi.nlm.nih.gov/pubmed/465413http://www.ncbi.nlm.nih.gov/pubmed/465413http://www.ncbi.nlm.nih.gov/pubmed/3174036http://www.ncbi.nlm.nih.gov/pubmed/3174036http://www.ncbi.nlm.nih.gov/pubmed/3174036http://www.ncbi.nlm.nih.gov/pubmed/3725324http://www.ncbi.nlm.nih.gov/pubmed/3725324http://www.ncbi.nlm.nih.gov/pubmed/8233387http://www.ncbi.nlm.nih.gov/pubmed/8233387http://www.ncbi.nlm.nih.gov/pubmed/8233387http://www.ncbi.nlm.nih.gov/pubmed/19685070http://www.ncbi.nlm.nih.gov/pubmed/19685070http://www.ncbi.nlm.nih.gov/pubmed/14021325http://www.ncbi.nlm.nih.gov/pubmed/14021325http://www.ncbi.nlm.nih.gov/pubmed/3653471http://www.ncbi.nlm.nih.gov/pubmed/3653471

incidence of ocular hypertension following silicone oil

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